Thermometer construction



Jan. '22, 1963 J. L. HOBIN THERMOMETER CONSTRUCTION Original Filed Feb.16, 1955 2 Sheets-Sheet 1 TW m mm K W. A 4 N Jan. 22, 1963 J. L. HOBINTHERMOMETER CONSTRUCTION Original Filed Feb. 16, 1955 2 Sheets-Sheet 2 il ng INVENTOR Joy/V Z A w/A ATTORNEYS Fnited rates 14 Claims. (Cl.73-340) This invention relates to temperature measuring devices and moreparticularly to improvements in indooroutdoor and other pluraltemperature thermometers, and to improved constructions of remotereading thermometer elements. This is a division of my copendingapplication Serial No. 488,45Q, filed February 16, 1955, now Patent No.2,846,881.

The prior art includes many plural temperature thermometers of widelyvarying construction suitable for indoor-outdoor and other plural andremote temperature indication. Certain of these known constructionsutilize a thermometer element of conventional integral stem and bulbtype for indicating indoor temperatures and, for outdoor temperatureindication, employ a remote reading thermometer element made up of aglass stem positioned adjacent the indoor thermometer element andinterconnected as by a length of metal capillary tubing to a remotelydisposed liquid-filled bulb located for exposure to outdoortemperatures. While some of the prior indooroutdoor thermometers of thistype have proven generally satisfactory in many applications, all aresubject to certain disadvantages commonly including difficulty and highcost of manufacture, poor accuracy of measurement, difficulty of readingand relatively short service life.

The present invention is directed to thermometers of the foregoinggeneral types and to remote reading thermometer elements therefor, andhas as its principal object the provision of new and improvedthermometer constructions which are fee of the above enumerated andother disadvantages of prior constructions as will be more fullyexplained hereinafter.

Perhaps the most troublesome difficulty encountered in the production ofthe most pertinent remote reading thermometer elements by methodsheretofore used resides in sealing the bendable capillary tubing, whichgenerally is of metal, to the glass stem of the thermometer. Theconventional method of effecting this seal includes the steps ofcounterboring or otherwise enlarging the bore of the lass stem at oneend, metallizing the enlarged portion of the bore and then soldering orbrazing the metal tube into the metallized bore, all of which operationsare relatively difiicult, time-consuming and costly. Moreover, thedifference in coefficients of thermal expansion of the glass stern andmetal tubing frequently cause breakage of the seal between the stem andtubing and occasionally of the glass stem itself.

I have found that these difficulties may be obviated and whollysatisfactory seals within normal ambient temperature Variation betweenthe glass stems and metal tubing of remote reading thermometer elementsobtained readily, uniformly and at minimum unit cost by use of settableplastic bonding agents as hereinafter more specifically described forsealing the tubing into the stem bores. By glass to metal sealing inthis manner, the need for costly metallizing and brazing apparatus asnecessary to prior constructions is entirely avoided, as is the need forskilled artisans such as required for the production of stem and tubingseals by methods heretofore em ployed.

Settable plastic bonding agents when utilized in accordance with theinvention and particularly when fortified smears Patented Jan, 22, 159%?by inclusion of frits or similar inorganic fillers as hereinafterexplained provide perfectly liquid tight seals having more than adequatemechanical strength to withstand normal abuse at all normal ambientatmospheric temperature and humidity conditions encountered in normalservice use. While the layer of plastic sealant between the stem boreand the inserted tubing hardens almost to ceramic consistency andprovides a connection between elements which to all appearances isperfectly rigid, still it retains sufficient elasticity to readilycompensate the difference in coefiicients of thermal expansion of theglass stem and metal tubing. Thus the possibility of breakage of theglass stem or of its seal to the tubing with expansion and contractiondue to temperature change is minimized in the theremometer constructionsof the present invention, assuring long and trouble-free service life.

Accordingly, it is a further object of the invention to provide new andimproved remote reading thermometer elements wherein settable plasticbonding agents are utilized in forming glass-to-metal seals.

More specifically, it is an object of the invention to provide novelremote reading thermometer elements each comprising a length of bendablemetal tubing sealed at one or both ends into a glass thermometer sternand/ or bulb by settable plastic bonding agents which may if de siredinclude a frit or similar inorganic filler material for enhancing thestrength of the glass-to-rnetal bond retained.

I have found that the ease and economy with which glass to metal sealsmay be effected in accordance with the invention and the quality of theseals thus produced permits making the temperature sensing bulb of theremote reading (outdoor) thermometer of glass rather than of metal ashas heretofore generally been the practice because of economic reasons.This is of particular advantage in that glass bulbs provide much betteraccuracy and reproducibility of temperature reading, due primarily totheir constancy of volumetric capacity at different temperatures,present and past. Metal bulbs do offer the advantages of good resistanceto breakage and quicker response to temperature change, but if desiredthese advantages may be retained in the temperature sensing bulbs ofthis invention by enclosing the glass bulbs within a protective sheathor capsule of heat conductive metal or the like.

It is accordingly another object of the invention to provid enew andimproved remote reading thermometer elements wherein the remotelydisposed temperature sensing bulbs are of glass. Still another object isthe provision of such thermometer elements wherein the glass bulbs areenclosed within protective and heat conductive metal sheaths.

These and other objects, features and advantages of the invention willbecome more fully apparent by reference to the appended claims and thefollowing detailed description when read in conjunction with theaccompanying drawings, wherein:

FIGURE 1 is a front elevation of an indoor-outdoor thermometer embodyingone form of the invention;

FIGURE 2 is a rear elevation of the thermometer of FIGURE 1 withportions of the casing back plate and thermometer card broken away toshow details of housing construction;

FIGURE 3 is an enlarged sectional veiw on line 3-3 of FIGURE 2;

FIGURE 4 is an enlarged sectional view of the remote reading (outdoor)thermometer stem and metal tubing assembly showing one form ofinterconnection of the stem and tubing;

FIGURE 5 is an exploded view showing one form of attachment of metaltubing to a glass temperature responsive bulb;

FIGURE 6 is an exploded view showing an alternative form of metal tubingand attachment to the thermometer stem or temperature responsive bulb;and

FIGURE 7 is a detail view showing a modified form of remote readingthermometer element utilizing a metallic temperature sensing bulb.

With continued reference to the drawings, wherein like referencenumerals are used throughout to designate like elements, theindoor-outdoor temperature thermometer selected for illustrationconstitutes one form of plural temperature thermometer embodying theinvention. This thermometer, generally designated by reference numeral10 in FIGURES 1 and 2, may comprise an elongated housing 12 enclosing athermometer card 14 on which are printed or otherwise inscribed suitabletemperature.

graduations as shown between the stems 16 and 18 of the indoor andoutdoor thermometer elements, respectively, thermometer stem 16 beingprovided with an integral glass bulb 20 and the stem 18 with a remotelylocated bulb 22 connected into the stem as by a length of flexible metalcapillary tubing 24.

The front wall 25 of housing 12 preferably is formed of a transparentplastic such as Lucite or other suitable molded plastic composition.Formed integrally with housing front wall 25 or otherwise securedthereto are rearwardly extending top, bottom, and side walls 26, 28 and30, respectively, which may be of the same plastic material as frontwall 25 and should be thermoplastic or otherwise deformable for a reasonwhich will later become apparent. As illustrated in FIGURES 2 and 3,each of these walls has formed in the inwardly facing side thereofstepped inner and outer shoulders or lands 32 and 33, respectively,preferably extending over the entire periphery of the chamber or recessdefined by.

the housing walls. Thermometer card 14, to which the two thermometertubes 16 and 18 may be attached 'as by staples 35, cementing or othersuitable means, seats on the inner shoulders 32 of housing 12 and isheld firmly pressed against this shoulder by a housingrclosure or backplate 3-7 as will later be described. Card 14 at its lower endterminates short of the bottom wall 28 of housing 12 and is held againstdisplacement toward the lower end of the housing by one or moreintegrally formed ribs or projections 39 upstanding from the shoulder 32and engaging the lower end of the card as shown. Back plate 37 fitssnugly within housing 12 with its periphery seated on the outer shoulder33 formed in the housing walls, the back plate being firmly held inposition against this shoulder 33 as by a plurality of tabs 41 whichpreferably are formed integrally with the thermoplastic material of thehousing walls and which extend rearwardly from shoulders 33 thereofthrough slots 43 provided in the periphery of the back plate. Initially,these tabs are straight and extend directly rearwardly of the housing asshown at 44 in FIGURE S. During assembly the tabs 41 are softened as byheating and then bent over and onto the back platetofix it, securelyagainst housing shoulder 33 as shown in FIGURES 2 "and 3.

Back plate 37 maybe providedwith suitable spacer means such as theintegrally formed projections or dimples 45' shown for maintaining theback plate and thermometer card 14 in mutually spaced relation and thecard firmly pressed against the inner shoulders 32 of the housing.Suitable mounting means such as the keyhole slots 47 illustrated may beprovided in b'ack plate 37 for mounting the instrument to a wall orother selected support.

The thermometer card, back plate and housing arrangement'just describedis of particular advantage because of its structural simplicity, itsbetter accuracy of reading due to the free suspension of the thermometertube lower ends, and its in.-'built allowancefor slight variations indimensions of elements which permits use 'of a stamped back plate asopposed to the fitted plates required in prior constructions.

The inherent flexibility of the thermometer card 14 and back plate 37permit the back plate projections 45 or such other spacer means as maybe provided between the back plate and thermometer card to be made of adepth sufficient to assure that the entire periphery of the thermometercard always is held firmly against the inner shoulders 32 in housing 12regardless of minor discrepancies in height of shoulders 32 and 33 dueto manufacturing inaccuracies. This arrangement also provides greaterease of assembly by obviating the need for careful alignment of partsduring assembly, and assures that card 14 will not loosen during theservice life of the instrument.

Since the temperature sensitive bulb 20 of the indoor temperaturethermometer tube 16 is suspended free of contact with housing 12, card14 and back plate 37, maximum accuracy of indoor air temperature isobtained andlittle if any error of indication is introduced by contactof the bulb with its supporting structure.

As noted above, thermometer card 14 may include only a single scale oftemperature indicia, these indicia preferably being located midwaybetween the two thermometer tubes for maximum speed and convenience oftemperature readings. As both thermometers are to read on this singlescale it accordingly is necessary to correlate temperature sensitivitiesof the two thermometers, as by proper selection of thermometer tube boresizes, bulb capacities and temperature sensitive fluids used. Itgenerally is preferred for purpose of economy to utilize fluids of thesame composition in both thermometer tubes, and since it is desirablethat the remotely disposed bulb of the outdoor thermometer be ofsubstantially greater size than the integral bulb of the indoorthermometer, it heretofore has not been possible to obtain equal indoorand outdoor temperature sensitivities for single scale indication usingindoor and outdoor thermometer stem bores of substantially the samesize, as in conventional indooroutdoor thermometer constructions.

In accordance with the invention, equal temperature sensitivities of theindoor and outdoorthermometers are obtained by relating thecross-sectional areas of the indoor and outdoor thermometer tube borescorrespondingly to the ratio of the volumetric capacities of theirrespective temperature sensing bulb assemblies, thus adjusting thesensitivity of the outdoor thermometer to the point where it issubstantially equal to that of the indoor one.

Several unobvious advantages follow from use of the thermometer stembore size relationship just described. Among these advantages iselimination of all need for stepping or counterboring the outdoorthermometer stem hole as has heretofore been necessary to accommodatethe inserted end of the capillary tubing for the temperature sensingbulb assembly. According to the invention, the bores of both thermometertubes may be uniform from end to end thereof, resulting in substantialsavings in manufacturing cost. Other important advantages reside in thereduced errors in reading due to changes in length of capillary tubingexposed to outdoor tempera-- tures, and in the broader angle and greaterrange of vision of the instrument and greater tolerance of align ment ofthe thermometer tubes with respect to the associated magnifying elementsnow to be described.

As shown in FIGURE 3, the indoor thermometer tube preferably is of thelens type having a generally triangular cross-section with a lens frontwhich provides a substantial degree of lateral magnification of thefluid column within the tube when viewed parallel to the attitude of thetriangular section, thus facilitating observation of fluid columnheight. In accordance with the invention, the tube 16 is canted aboutits longitudinal axis so that the altitude of the triangular section orlens front is tilted slightly with respect to normal to the back plate37 to Which the tube is mounted, thus assuring that greatestmagnification and best vision of the tube will be obtained when theviewer stands a normal distance from the instrument and somewhere alonga perpendicular from approximately the center of the back plate.Thermometer tube 16 may conveniently be fixed in such canted position byproper shaping of its mounting staples 35 as shown.

Outdoor thermometer tube 18 preferably is although not necessarilyprovided with similar in-built magnification means and may if desired becanted similarly but oppositely to the indoor tube, though because ofits substantially wider bore the exact alignment of the outdoorthermometer tube is not critical. Therefore, if the indoor thermometertube has been properly aligned, both tubes may easily be viewed fromdirectly in front of the instrument regardless of whether the outdoortube is or is not similarly accurately aligned.

The magnification in-built into the thermometer tubes may if desired besupplemented by cylindrical magnifying lens surfaces formed in thetransparent front wall 25 of casing 12 as illustrated in FIGURE 3. Asthere shown, the casing is shaped in cross-section to provide apredetermined degree of lateral magnification of the centrally disposedscale of temperature graduations for the thermometer tubes, and agreater degree of lateral magnification of the thermometer tubes proper.The exact shape of these magnifying strips necessary to provide thedesired different degrees of magnification may readily be determinedfrom well known principles of geometrical optics, as will be understoodby those skilled in the art. If desired, only the front surface ofcasing wall 25 may be made convexly curved, the back surface being madeplane as shown in the above mentioned Patent No. 2,460,- 051 to Welch.

Preferably, both thermometer tubes are provided with the conventionalwhite background strip (not shown) running along the rear of the tubesfor enhancing visibility of the fluid columns therein.

Turning now to preferred constructions of the outdoor temperaturesensing bulb assembly and its capillary tubing and tubing connectionsinto the bulb and thermometer tube, FEGURE 4 illustrates one form ofmetal capillary tubing 24 and shows its attachment into the thermometerstem 1%. As shown, the thermometer tube bore 53 may in accordance withthe invention be of uniform diameter along the entire length thereof,thus avoiding the stepped bores and attendant high cost of previousconstructions.

Capillary tubing 55 in FIGURE 5 preferably is thinwalled stainless steelwhich I have found need not be armored as is the case with priorthin-walled copper tubing which is conventionally armored as by abraided metal sheath 57 for protection against collapse due to sharpbending or other cause. Use of stainless steel capillary tubing with theimproved plastic metal to glass seal accordingly results in asubstantial cost reduction in remote indicating thermometer elementsover the prior elements utilizing armored copper tubing. The tubingpreferably has an outside diameter such that it fits loosely within thebore 53 of stem 18, and is cemented and sealed into the bore by a bodyof settable plastic cement indicated at 59 in FIGURE 4 as willhereinafter be more fully described. A coil spring 61 may be fitted overthe end of thermometer stem 18 as shown and boned to the stem and to aportion of the length of the tubing 5'5 or its braided sheath 57 whenused, by the settable plastic cement 59, thus substantiallystrengthening and reinforcing the joint between the stem and tubing.Spring 61 also serves to resist excessively sharp bending of thecapillary tubing with consequent collapse thereof particularly at thepoint at which the tubing enters the stem.

While spring 6 1 provides these important advantages in the structurejust described, its presence is not essential and if desired it may beomitted. An adequately strong bond and seal between the stem and tubingwill be ob- 6 tained even in the absence of spring 61, using plasticcements of the type and in the manner now to be described.

The cement used may be any thermoplastic, thermosetting or catalystsetting plastic capable of securely bonding both to metal and to glass,to provide a mechanically strong bond and fluid tight seal between suchmaterials. I have found particularly suitable, however, the epoxy resintype plastics identified as A-2 and X-Z and sold by Armstrong ProductsCompany, which identifies these plastics as being two-component systemsconsisting of an epoxy resin formulation and an amine type catalyst, oneor both these components having admixed therein a f-rit or otherinorganic filler. Preferably, relatively high percentages of suchinorganic filler are included in the plastic as used in the presentapplication, since this provides stronger bonds between the metal tubingand thermometer stems.

In use, the components of the plastic are mixed to form a waterysubstance which readily flows into the small space between the looselyfitting metal tubing and thermometer stem, which preferably arethoroughly precleaned and degreased as by suitable solvents or othercleansing or etching agents before assembly. The plastic wets theopposing surfaces of the thermometer stem .and tubing, fills any spacebetween these elements and hardens almost to ceramic consistency whenproperly cured at room or elevated temperatures, the exact details ofthe curing process depending on the particular plastic formulationemployed. Sufiicien-t of the plastic also is distributed over theexterior of the thermometer stem and tubing ends and over tubing sheath57 and spring 61 to securely bond together all these elements and thusgreatly enhance the strength of the stem to tubing area.

The glass-to-metal bond obtained in this manner is good up to about F.and above, and while bond strength may decrease slightly at these highertemperatures this is relatively unimportant since such temperatures areseldom if ever encountered in normal service use.

Capillary tubing 55 is sealed at its end remote from thermometer stem 18into a temperature sensing bulb assembly one form of which isillustrated in the exploded view of FIGURE 5. As there shown, the bulbassembly 63 may comprise a hollow glass bulb 65, a coil spring 67similar in purpose and structure to spring 61 described above, and aheat conductive metal capsule or sheath 6? of a size to fit over bulb 65for protecting it against break age and improving its time of responseto temperature change.

Tubing 55 and its protective sheath 57, and bulb 65' and spring 67 maybe interfitted and securely bonded together by use of a plastic cementof the type and in the manner described above in reference to attachmentof the tubing into the thermometer stern. Preferably the end of capsule69 through which the tubing projects also is bonded thereto and to thetubing sheath and spring by plastic cement distributed over theseelements. The other end of capsule 6% may be plugged and bulb 65securely fixed in position in the capsule by a quantity of plasticpoured or otherwise placed in the open end of the capsule after assemblyand there permitted to harden.

I have found that equally good bonds between stainless steel tubing andglass thermometer stems or bulbs may be obtained as with copper tubingeither armored or unarmored, and :as hereinbefore pointed out, since thestainless steel tubing has much greater mechanical strength than copper,it presents very satisfactory resistance to collapse and other injurywithout use of any protective sheath or armor such as that illustratedin FIG- URES 15, for example. However, as the result of recentimprovements in copper tubing strength, I have found that unarmoredcopper tubing can be satisfactorily used.

Tubing of the unarmored type just described is illus- 7 trated in FIGURE6; wherein the capillary tubing 71 is of stainless steel or copper andas shown is unarmored throughout its length. FIGURE 6 also illustratesa'modified formrof attachment of the tubing end into either thethermometer stem or temperature sensing bulb, the latter beingspecifically shown.

In FIGURE 6, coil springs such as shown at 61 and 67 in FIGURES 4 and 5for reinforcing the tubing joint are omitted, a simple cap fitting 73being instead used if necessary for joint reinforcement. This capfitting is bonded to tubing 71 and to the glassbulb 75 and its enclosingcapsule 77 by plastic cementing in a manner similar to that describedabove, the open end of capsule 77 then being plugged by plastic as alsodescribed in the foregoing.

Tubing to bulb joints utilizing plastic bonding agents in accordancewith the invention also may be efiected using metal bulbs, though inview of the better accuracy and reproducibility of readings provided byglass bulbs these generally are preferred. If for economy or otherreasons metal bulbs are to be used, however, good bulb to tubing jointsmay be easily and economically obtained simply by flowing a plasticcomposition as described above over and into the tubing to bulb jointand permitting the plastic to harden.

Such an arrangement is, illustrated in FIGURE 7, wherein a length ofcapillary tubing '79 preferably fabricated of stainless steel or copperis inserted and sealed into the neck of a metal bulb 81 also preferablyof the same metal as the capillary tubing, by a body of plastic cement83. If desired, a cap fitting such as shown at 73 in FIGURE 6 may beincluded for reinforcing the tubing to bulb joint thus provided.

As is apparent from the foregoing, the indoor-outdoor thermometers ofthepresent invention present the important advantages of simplicity ofstructure, ease and economy of manufacture, good accuracy of temperatureindication and long expected servicelife. While the in-v vention hasbeen specifically described with reference to indoor-outdoorthermometers it will be understood that in many of its aspects theinvention is equally applicable to other plural temperaturethermometers, remote reading thermometers and temperature measuringdevices generally.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. In a remote reading thermometer,

(a) a hollow glass member having an internal cavity opening through awall thereof;

(b) a length of capillary metal tubing having an end with a slightlylesser external cross section than the internal cross section of saidopening received in said opening and being armored by a flexible sheath;

(c) a tubular reinforcement element substantially coaxially surroundingand overlying portions both of said hollow glass member and of saidtubing, and being in contacting relationship with said flexible sheath;and

(d) a body of settable plastic cement interposed between the exterior ofsaid tubing end and the interior wall of said opening for sealing saidtubing in said opening, said cement body also bonding said reinforcementelement to portions of the glass member, the tubing and to the flexiblesheath.

2. In a remote reading thermometer,

(a) a hollow glass member having an internal cavity opening through awall thereof;

(b) a length of capillary metal tubing having an end with slightlylesser external cross-section than the internal cross-section of saidopening received in said opening;

(0) a body of settable plastic cement interposed between the exterior ofsaid tubing end and the interior wall of said opening and sealing saidtubing in said opening; and

(d) a flexible sheath serving as an armor for said tubing and extendinginto and being bonded to said body of settable plastic cement.

3. In a remote reading thermometer,

(a) a hollow glass bulb member adapted to contain a temperaturesensitive liquid and having an internal cavity opening through a wallthereof;

(b) a length of capillary metal tubing having an end with slightlylesser external cross-section than the internal cross-section of saidopening received in said opening;

(0) a body of settable plastic cement interposed between the exterior ofsaid tubing end and the interior wall of said opening and sealing saidtubing in said opening; and

(d) an elongate metal sheath enclosing said bulb and having one endadjacent said tubing and bonded thereto by said settable plastic cement.

4. The combination defined in claim 3 wherein the other end of saidmetalsheath is closed and said bulb sealed therein by a second body ofsetta-ble plastic cement disposed in said sheath end.

5. In a remote reading thermometer, the combination of:

(a) a hollow glass thermometer member including wall means defining aninternal cavity having an opening to the exterior of the member,

(b) a length of metal capillary tubing having one end received in saidopening, and

(c) ,a body of settable plastic epoxy resin composition including as aningredient an inorganic filler interposed between the exterior surfaceof said tubing end and the interior surface of said opening definingwall means for sealing the tubing end into said opening.

6. The remotereading therometer as defined in claim 5 wherein saidinorganic filler is a frit.

7. The remote reading thermometer as defined in claim 5 wherein theglass thermometer member is a thermometer tube, the internal cavity is acapillary bore in the thermometer tube, the metal tubing extends intothe thermometer tube bore Slll'fiClfiIllilY far to avoid beingobstructed by the epoxy resin body, and the body of epoxy resin extendsover the metal tubing at the end adjacent the thermometer tube and overthe thermometer tube end and along outer side walls ofthe thermometertube to assist bonding the thermometer tube and metal tubing together.

8. The remote reading thermometer as defined in claim 7 furtherincluding a tubular reinforcement element substantially coaxiallysurrounding and overlying portions both of said thermometer tube and ofsaid metal tubing, said element being bonded to said portions of saidtube and tubing by said epoxy resin body.

9. The remote reading thermometer as defined in claim 8 wherein saidreinforcement element is in the form of a claim 10 wherein saidreinforcement element is in the form of a coil spring.

13. A method of providing a seal between a glass thermometer memberhaving a bore and a metal capillary tubing for use in a remote readingthermometer comprising the steps of:

(a) providing a length of metal capillary tubing having an outerdiameter no greater than the bore diameter in said thermometer member;

(b) inserting one end of the metal tubing in said bore;

(0) applying a settable plastic epoxy resin composition including as aningredient an inorganic filler, said composition being applied as aliquid to the junction of the glass thermometer member and the metaltubing to spread between the exterior surface of a portion of the metaltubing extending into the thermometer tubin and the thermometer bore,but Without obstructing the metal tubing bore; and

(d) curing said settable composition to form a complete bond betweensaid thermometer member and said metal tubing.

14. The method as defined in claim 13 wherein said inorganic filler in afrit, and said epoxy resin composition is applied to extend along theoutside surfaces both of said glass thermometer member and said metaltubing to provide a joint of increased strength against separation ofthe metal tubing from the glass member.

References Cited in the file of this patent UNITED STATES PATENTS373,742 Keiser Nov. 22, 1887 659,616 Briston et a1 Oct. 9, 19001,081,139 Parliman Dec. 9, 1913 1,298,075 Malone Mar. 25, 1919 1,616,519Twombly Feb. 8, 1927 1,706,609 Horelick Mar. 2 6, 1929 1,811,190 TateJune 23, 1931 1,841,908 Noble Jan. 19, 1932 2,267,556 Eisele Dec. 23,1941 2,336,092 Grooms Dec. 7, 1943 2,374,055 Treanor Apr. 17, 19452,374,377 Percy Feb. 4, 1947 2,415,309 Stone Feb. 4, 1947 2,712,237Margolis July 5, 1955 2,725,748 Liberatore Dec. 6, 1955 2,826,625MacDonald Mar. '11, 1958 2,828,235 Holland et al Mar. 25, 1958 UNITEDSTATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,074,275January 22,, 1963 John L. Hobin It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

Column 2', lines 48 and 49, forv 'provid e'new" read provide-new column4, line 70, for"attituole; readaltitude; column 5, line 64, for "boned"vread----b0nd-ed- Signed and sealed this 24th day of September 1963(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents

1. IN A REMOTE READING THERMOMETER, (A) A HOLLOW GLASS MEMBER HAVING ANINTERNAL CAVITY OPENING THROUGH A WALL THEREOF; (B) A LENGTH OFCAPILLARY METAL TUBING HAVING AN END WITH A SLIGHTLY LESSER EXTERNALCROSS SECTION THAN THE INTERNAL CROSS SECTION OF SAID OPENING RECEIVEDIN SAID OPENING AND BEING ARMORED BY A FLEXIBLE SHEATH; (C) A TUBULARREINFORCEMENT ELEMENT SUBSTANTIALLY COAXIALLY SURROUNDING AND OVERLYINGPORTIONS BOTH OF SAID HOLLOW GLASS MEMBER AND OF SAID TUBING, AND BEINGIN CONTACTING RELATIONSHIP WITH SAID FLEXIBLE SHEATH; AND (D) A BODY OFSETTABLE PLASTIC CEMENT INTERPOSED BETWEEN THE EXTERIOR OF SAID TUBINGEND AND THE INTERIOR WALL OF SAID OPENING FOR SEALING SAID TUBING INSAID OPENING, SAID CEMENT BODY ALSO BONDING SAID REINFORCEMENT ELEMENTTO PORTIONS OF THE GLASS MEMBER, THE TUBING AND TO THE FLEXIBLE SHEATH.